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72 JAIX PHILOSOPHY & DIODEIN SCIENCE doubted the "Theory of the Elements' as the primary cause, which was current from the time of Thales His belief was that these five elements are not primary even The primary elements are different from these, and they were the result of the combination of such elements Up to that time, air was not considered to possess mess It Was Boyle, wiko, for the first tim proved, that air also has mass Up to that time 'arm was mostly recognised as a priramy element Though various kinds of gases were discovered, they were considered as being differert modes of 'air
In 1755, Blank, an Englishman, for the first time, discovered carbondioxide. He named it as 'fixed ar' Priestley (1774) discovered oxygen, one of the present day primary chemical elements, and showed that it is essential for lighting fire and for the breathing of living beings Hendry Cavendish proved that water was a combination of oxygen and hydrogen The conception that water is a primary element was removed from that time A molecule or the smallest particle of water is formed by the combination of two atoms of hydrogen and one atom of oxygen Works of Greek scholars were looked upon with great reverence in Europe, until the results of new researches began to appear in the field of physical science Galileo, Newton and Boyle held great respect for the Atomic Theory of Democritus John Dalton for the first time clearly demonstrated
